Even though diamonds, emeralds, and other gemstones are perfect as the centerpiece of every necklace, you don’t have to spend thousands on expensive stones for a beautiful crystal. Take this gold necklace, for example - at the center of the necklace is not a diamond, but a Swarovski crystal, which is essentially high-quality crystal glass. It may not be a gemstone, but you’d bet that many people would think it is one.